[Alneyan]

You have to login on PBW, go to the list of Open Games (if you are using the text Version, click on the Game button above, and then on Open Game in the left frame) and select the Star Wars Mod II game. Then click on join the game (if using the text Version of PBW), or the corresponding graphic icon for the other Version.

The game owner will then have to approve you before you can do anything else. Then, you will have to make your Empire file and upload it, but this will come later on.